1. Field of the Invention
The present invention relates to a digital camera and an image data processing system comprising an image pickup function, which picks up an image with a solid-state image pickup device and performs photoelectric transfer to obtain analog image data, and a digital image data recording function which converts the analog image data to form digital image data and records the data on a recording medium.
2. Description of the Related Art
In conventional digital cameras, when a still image or the like is picked up with a Charged Coupled Device (CCD), after the image data is converted from analog to digital, it is compressed with a predetermined compression format (e.g., JPEG), recorded, and stored in a recording medium such as a memory card.
The compressed and stored image data (hereinafter referred to as “JPEG data”) is decompressed and displayed when reproducing the data onto the liquid-crystal monitor on the digital camera. When an index image or the like is displayed, a thumbnail image is prepared independently of the JPEG compressed image. This thumbnail image is read out to shorten the read-out process time.
Digital cameras can be easily connected to an external  control device (e.g., personal computer) so that image data recorded on a recording medium can be transferred thereto, subjected to various processes, and then printed out. Hence, digital cameras have become increasingly popular in recent years.
In particular, images photographed with a digital camera are often applied to business purposes. For professional uses, when a high-quality photographed image is compressed once, depending on the compression rates, the image quality or the like of the compressed image may be lower than that of the originally obtained photographed image data.
Therefore, conventional technology proposes a digital camera having a raw image recording control function, in addition to the compressed image recording control function. That is, a photographed image is recorded as raw image data (hereinafter referred to as CCD-raw data) on a recording medium so that the CCD-raw data is transferable to a personal computer (see Japanese Patent Application Laid-Open (JP-A) Nos. 6-90435 and 11-261933).
As disclosed in the above conventional technology, unlike normal JPEG data, CCD-raw data is not subjected to necessary processes to reproduce and display the data on the liquid-crystal monitor of the digital camera. For this reason, interpolation automatic exposure (AE), automatic white balance (AWB), gamma adjustment, and the like must be performed when reproducing the CCD-raw data. For this reason, such digital cameras must be equipped with a function that enables execution of a reproduction process of the CCD-raw data.
When a CCD-raw data reproducing process function is arranged in the digital camera in advance, the data can be reproduced and displayed on the liquid-crystal monitor.
However, the CCD-raw data is generated on the assumption that it will be transferred to an external image processing device such as a personal computer and processed therein, and then recorded onto a recording medium. In order to reproduce and display such CCD-raw data, dedicated application software (hereinafter referred to as a “dedicated viewer”) must be installed in the personal computer. However, since CCD-raw data is for professional and not general use, it has poor versatility and further, not all personal computers possess dedicated viewers for the CCD-raw data.
For this reason, the conventional technology is problematic in that when a photographing operation is erroneously performed in a CCD-raw mode, there are cases where the obtained CCD-raw data cannot be reproduced on a personal computer.